Conflicts:
	block/blk-core.c
	block/blk-flush.c
	drivers/md/raid1.c
	drivers/md/raid10.c
	drivers/md/raid5.c
	fs/nilfs2/btnode.c
	fs/nilfs2/mdt.c
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

Use plug in throttle dispatch also as we are dispatching a bunch of
bios in throttle context and some of them might merge.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

With the plugging now being explicitly controlled by the
submitter, callers need not pass down unplugging hints
to the block layer. If they want to unplug, it's because they
manually plugged on their own - in which case, they should just
unplug at will.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

This should be useless now that we have on-stack plugging. So lets just
kill it.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

Code has been converted over to the new explicit on-stack plugging,
and delay users have been converted to use the new API for that.
So lets kill off the old plugging along with aops->sync_page().
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

This patch adds support for creating a queuing context outside
of the queue itself. This enables us to batch up pieces of IO
before grabbing the block device queue lock and submitting them to
the IO scheduler.

The context is created on the stack of the process and assigned in
the task structure, so that we can auto-unplug it if we hit a schedule
event.

The current queue plugging happens implicitly if IO is submitted to
an empty device, yet callers have to remember to unplug that IO when
they are going to wait for it. This is an ugly API and has caused bugs
in the past. Additionally, it requires hacks in the vm (->sync_page()
callback) to handle that logic. By switching to an explicit plugging
scheme we make the API a lot nicer and can get rid of the ->sync_page()
hack in the vm.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

It was always abuse to reuse the plugging infrastructure for this,
convert it to the (new) real API for delaying queueing a bit. A
default delay of 3 msec is defined, to match the previous
behaviour.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

It was always abuse to reuse the plugging infrastructure for this,
convert it to the (new) real API for delaying queueing a bit.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
Acked-by: David S. Miller <davem@davemloft.net>

Currently we use plugging for that, but as plugging is going away,
we need an alternative mechanism.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

Convert two staging drivers - blkvsc_drv and cyasblkdev_block - from
->media_changed() to ->check_events().  The former always indicated
media changed while the latter always indicated media not changed.
Not sure what the drivers are trying to achieve but keep the original
behavior.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kay Sievers <kay.sievers@vrfy.org>

Convert from ->media_changed() to ->check_events().

pktcdvd needs to forward all event related operations to the
underlying device.  Forward ->check_events() instead of
->media_changed() and inherit disk->[async_]events.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Peter Osterlund <petero2@telia.com>

umem doesn't implement media changed detection and there's no need to
implement dummy callback anymore.  Remove it.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kay Sievers <kay.sievers@vrfy.org>

Convert from ->media_changed() to ->check_events().

s390/tape_block buffers media changed state and clears it on
revalidation.  It will behave correctly with kernel event polling.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>

Convert from ->media_changed() to ->check_events().

i2o_block buffers media changed state and clears it after reporting.
It will behave correctly with kernel event polling.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Markus Lidel <Markus.Lidel@shadowconnect.com>

Convert from ->media_changed() to ->check_events().

xsysace buffers media changed state and clears it on revalidation.  It
will behave correctly with kernel event polling.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Grant Likely <grant.likely@secretlab.ca>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kay Sievers <kay.sievers@vrfy.org>

Convert from ->media_changed() to ->check_events().

ub buffers media changed state and clears it on revalidation.  It will
behave correctly with kernel event polling.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Pete Zaitcev <zaitcev@redhat.com>

Convert from ->media_changed() to ->check_events().

Both swim and swim3 buffer media changed state and clear it on
revalidation.  They will behave correctly with kernel event polling.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Laurent Vivier <laurent@lvivier.info>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>

Convert from ->media_changed() to ->check_events().

DAC960 media change notification seems to be one way (once set, never
cleared) and will generate spurious events when polled once the
condition triggers.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kay Sievers <kay.sievers@vrfy.org>

Convert paride drivers from ->media_changed() to ->check_events().

pcd and pd buffer and clear events after reporting; however, pf
unconditionally reports MEDIA_CHANGE and will generate spurious events
when polled.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Tim Waugh <tim@cyberelk.net>

Convert gdrom and viocd from ->media_changed() to ->check_events().

It's unclear how the conditions are cleared and it's possible that it
may generate spurious events when polled.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kay Sievers <kay.sievers@vrfy.org>

Convert the floppy drivers from ->media_changed() to ->check_events().
Both floppy and ataflop buffer media changed state bit and clear them
on revalidation and will behave correctly with kernel event polling.

I can't tell how amiflop clears its event and it's possible that it
may generate spurious events when polled.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kay Sievers <kay.sievers@vrfy.org>

Convert ->media_changed() to the new ->check_events() method.  The
conversion is mostly mechanical.  The only notable change is that
cdrom now doesn't generate any event if @slot_nr isn't CDSL_CURRENT.
It used to return -EINVAL which would be treated as media changed.  As
media changer isn't supported anyway, this doesn't make any
difference.

This makes ide emit the standard disk events and allows kernel event
polling.  Currently, only MEDIA_CHANGE event is implemented.  Adding
support for EJECT_REQUEST shouldn't be difficult; however, given that
ide driver is already deprecated, it probably is best to leave it
alone.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Jens Axboe <axboe@kernel.dk>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: linux-ide@vger.kernel.org

Not all block drivers clear events immediately after reporting.  Some
do so in ->revalidate_disk() or other steps during ->open().  There is
a slim chance event poll may happen between the clearing event check
from check_disk_change() and the actual clearing of the events which
would result in spurious events.

Block event checks while block device open is in progress.  There is
no need to kick explicit event check afterwards as events are always
checked during open.

-v2: The original patch could have called disk_unblock_events() with
     an already released or %NULL @disk causing oops.  Fixed by making
     sure references are put after disk_unblock_events() is called.
     It also makes the error path of __blkdev_get() a bit simpler.
     This problem was reported by Jens.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kay Sievers <kay.sievers@vrfy.org>

The block event mechanism currently always checks events when the
device is being closed regardless of the open mode.  The intention was
to allow detection of EJECT_REQUEST when a device is closed whether
disk event polling is enabled or not.

This is unnecessary as, for devices of interest, events are checked
from either userland or kernel and in the former case ->check_events()
is performed on open of each poll attempt anyway.  Furthermore, this
unconditional event check on close makes the code susceptible to event
loop if the block driver doesn't clear reported events correctly - an
event triggers userland to open and close the device which in turn
causes another event, rinse and repeat.

Check events on close only if it was blocked by excl write open.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kay Sievers <kay.sievers@vrfy.org>

Currently, disk_unblock_events() implicitly kick event check if the
block count reaches zero.  This behavior is not described in the
comment and hinders with future changes.  Make the unblocker
explicitly check events by calling disk_check_events() as necessary.

This patch doesn't cause any behavior difference.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Kay Sievers <kay.sievers@vrfy.org>

We've found that we still get good, useful isolation at weights this
low. I'd like to adjust the minimum so that any other changes can take
these values into account.
Signed-off-by: Justin TerAvest <teravest@google.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

The block integrity subsystem no longer uses the bio_vec slabs so this
code can safely be compiled in.
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

When throttle group limits are updated through cgroups, a thread is
woken up to process these updates. While reviewing that code, oleg noted
couple of race conditions existed in the code and he also suggested that
code can be simplified.

This patch fixes the races simplifies the code based on Oleg's suggestions:

	- Use xchg().
	- Introduced a common function throtl_update_blkio_group_common()
          which is shared now by all iops/bps update functions.
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>

Fixed a merge issue, throtl_schedule_delayed_work() takes throtl_data
as the argument now, not the queue.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

With the help of cgroup interface one can go and upate the bps/iops
limits of existing group. Once the limits are udpated, a thread is
woken up to see if some blocked group needs recalculation based on new
limits and needs to be requeued.

There was also a piece of code where I was checking for group limit
update when a fresh bio comes in. This patch gets rid of that piece of
code and keeps processing the limit change at one place
throtl_process_limit_change().  It just keeps the code simple and easy
to understand.
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

Merge branch 'block-for-2.6.39-core' of ssh://master.kernel.org/pub/scm/linux/kernel/git/tj/misc into for-2.6.39/core

The update_vdisktime logic is broken since commit
b54ce60e, st->min_vdisktime never makes
a progress. Fix it.

Thanks Vivek for pointing it out.
Signed-off-by: Gui Jianfeng <guijianfen@cn.fujitsu.com>
Acked-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

If there are a sync and an async queue and the sync queue's think time
is small, we can ignore the sync queue's dispatch quantum. Because the
sync queue will always preempt the async queue, we don't need to care
about async's latency.  This can fix a performance regression of
aiostress test, which is introduced by commit f8ae6e3e. The issue
should exist even without the commit, but the commit amplifies the
impact.

The initial post does the same optimization for RT queue too, but since
I have no real workload for it, Vivek suggests to drop it.
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Reviewed-by: Gui Jianfeng <guijianfeng@cn.fujitsu.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

We need to hold the queue lock over the reference increment,
it's not atomic anymore.
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

This merge creates two set of conflicts.  One is simple context
conflicts caused by removal of throtl_scheduled_delayed_work() in
for-linus and removal of throtl_shutdown_timer_wq() in
for-2.6.39/core.

The other is caused by commit 255bb490 (block: blk-flush shouldn't
call directly into q->request_fn() __blk_run_queue()) in for-linus
crashing with FLUSH reimplementation in for-2.6.39/core.  The conflict
isn't trivial but the resolution is straight-forward.

* __blk_run_queue() calls in flush_end_io() and flush_data_end_io()
  should be called with @force_kblockd set to %true.

* elv_insert() in blk_kick_flush() should use
  %ELEVATOR_INSERT_REQUEUE.

Both changes are to avoid invoking ->request_fn() directly from
request completion path and closely match the changes in the commit
255bb490.
Signed-off-by: Tejun Heo <tj@kernel.org>

Following steps lead to deadlock in kernel:

dd if=/dev/zero of=img bs=512 count=1000
losetup -f img
mkfs.ext2 /dev/loop0
mount -t ext2 -o loop /dev/loop0 mnt
umount mnt/

Stacktrace:
[<c102ec04>] irq_exit+0x36/0x59
[<c101502c>] smp_apic_timer_interrupt+0x6b/0x75
[<c127f639>] apic_timer_interrupt+0x31/0x38
[<c101df88>] mutex_spin_on_owner+0x54/0x5b
[<fe2250e9>] lo_release+0x12/0x67 [loop]
[<c10c4eae>] __blkdev_put+0x7c/0x10c
[<c10a4da5>] fput+0xd5/0x1aa
[<fe2250cf>] loop_clr_fd+0x1a9/0x1b1 [loop]
[<fe225110>] lo_release+0x39/0x67 [loop]
[<c10c4eae>] __blkdev_put+0x7c/0x10c
[<c10a59d9>] deactivate_locked_super+0x17/0x36
[<c10b6f37>] sys_umount+0x27e/0x2a5
[<c10b6f69>] sys_oldumount+0xb/0xe
[<c1002897>] sysenter_do_call+0x12/0x26
[<ffffffff>] 0xffffffff

Regression since 2a48fc0a, which introduced the private
loop_mutex as part of the BKL removal process.

As per [1], the mutex can be safely removed.

[1] http://www.gossamer-threads.com/lists/linux/kernel/1341930

Addresses: https://bugzilla.novell.com/show_bug.cgi?id=669394
Addresses: https://bugzilla.kernel.org/show_bug.cgi?id=29172Signed-off-by: Petr Uzel <petr.uzel@suse.cz>
Cc: stable@kernel.org
Reviewed-by: Nikanth Karthikesan <knikanth@suse.de>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

If we enable trace events to trace block actions, We use
blk_fill_rwbs_rq to analyze the corresponding actions
in request's cmd_flags, but we only choose the minor 2 bits
from it, so most of other flags(e.g, REQ_SYNC) are missing.
For example, with a sync write we get:
write_test-2409  [001]   160.013869: block_rq_insert: 3,64 W 0 () 258135 + =
8 [write_test]

Since now we have integrated the flags of both bio and request,
it is safe to pass rq->cmd_flags directly to blk_fill_rwbs and
blk_fill_rwbs_rq isn't needed any more.

With this patch, after a sync write we get:
write_test-2417  [000]   226.603878: block_rq_insert: 3,64 WS 0 () 258135 +=
 8 [write_test]
Signed-off-by: Tao Ma <boyu.mt@taobao.com>
Acked-by: Jeff Moyer <jmoyer@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>